In a discussion between Williams and NBC News' Dr. Nancy Snyderman, the anchor describes the recovery from surgery and ensuing physical therapy.

"I have worked hard with a lot of help from really good physical therapists," said Williams. "You have to be a motivated patient, and I was a motivated patient. I was motivated to get out of 30 years of knee pain."

Williams announced the surgery on his Aug. 1 show in a segment on chronic knee pain.